1. Field of the Invention
The present invention relates to conveyance devices. More specifically, the present invention relates to controlling a conveyance device to transfer objects from one conveyor to a second conveyor in an assembly line and still more specifically, the present invention relates to a means for transferring carton blanks from a conveyor at one speed to a conveyor of another speed.
2. Description of the Related Art
Various conveyance devices are commonly used to transport blanks or stock material from a feeder, through an assembly line or process, to an end point where a finished product results. For example, in the production of packaging, cardboard, paperboard or corrugated blanks are moved through a folder/gluer to transform the blank into a completed box. A feeder is provided that receives a store of blanks. The blanks are removed in an automated fashion from the feeder and moved along a belt system, where they are introduced into various modules. Each module completes a specific action. For example, each module might make a specific fold or glue a specific portion.
The transitions from the feeder to the first module is important. That is, the blanks are essentially stored in stacked relationship within the feeder and are rapidly and sequentially transferred to the first module. Thus, there is a tension between providing the blanks as rapidly as the module can process them and accurately feeding them into that module. For example, in some systems any given section of a conveyer includes four belts that are relatively narrow in comparison to the blank: two upper sections generally aligned at or near the edge and two lower sections similarly aligned with the edge. Thus, if a blank enters this section of conveyor askew or if the belts are not running in synchronicity, the blank may be shifted out of its proper orientation. When improperly positioned, the remaining modules may not properly process the blank.
In addition, because many feeders dispense the blanks in an end-to-end relationship with no gap, or minimal gap, between adjacent blanks, and because a gap is necessary for the downstream modules to properly process the blanks, the speed of the downstream module belts (the line speed) is greater than the feeder belt speed.
The fact that the blanks must be transferred from a slower moving feeder belt speed to a faster moving line belt speed creates additional problems. The first is excessive belt wear resulting from one or more belts sliding over a portion of the blank because of the speed differential. The second is the wearing such sliding will produce on the blanks, particularly with respect to printed matter.
Thus, there exists a need to provide properly spaced, appropriately aligned blanks to a processing module while reducing and minimizing belt wear and damage to the blanks.